Refactored fast TGA writer into its own class to be able to share the

code between the Screenshot class and the anticipated tile rendering
library.


git-svn-id: file:///usr/local/projects/SUN/JOGL/git-svn/svn-server-sync/jogl/trunk@577 232f8b59-042b-4e1e-8c03-345bb8c30851

2 files changed, 125 insertions, 26 deletions

diff --git a/src/classes/com/sun/opengl/util/Screenshot.java b/src/classes/com/sun/opengl/util/Screenshot.java
index d91e7f8f5..e552da53e 100755
--- a/src/classes/com/sun/opengl/util/Screenshot.java
+++ b/src/classes/com/sun/opengl/util/Screenshot.java
@@ -48,8 +48,6 @@ import javax.media.opengl.glu.*;
 /** Utilities for taking screenshots of OpenGL applications. */
 
 public class Screenshot {
-  private static final int TARGA_HEADER_SIZE = 18;
-
   private Screenshot() {}
 
   /** 
@@ -98,32 +96,13 @@ public class Screenshot {
                                       int width,
                                       int height,
                                       boolean alpha) throws GLException, IOException {
-    RandomAccessFile out = new RandomAccessFile(file, "rw");
-    FileChannel ch = out.getChannel();
-    int pixelSize = (alpha ? 32 : 24);
-    int numChannels = (alpha ? 4 : 3);
-    int readbackType = (alpha ? GL.GL_ABGR_EXT : GL.GL_BGR);
     if (alpha) {
       checkExtABGR();
     }
 
-    int fileLength = TARGA_HEADER_SIZE + width * height * numChannels;
-    out.setLength(fileLength);
-    MappedByteBuffer image = ch.map(FileChannel.MapMode.READ_WRITE, 0, fileLength);
-
-    // write the TARGA header
-    image.put(0, (byte) 0).put(1, (byte) 0);
-    image.put(2, (byte) 2); // uncompressed type
-    image.put(12, (byte) (width & 0xFF)); // width
-    image.put(13, (byte) (width >> 8)); // width
-    image.put(14, (byte) (height & 0xFF)); // height
-    image.put(15, (byte) (height >> 8)); // height
-    image.put(16, (byte) pixelSize); // pixel size
-             
-    // go to image data position
-    image.position(TARGA_HEADER_SIZE);
-    // jogl needs a sliced buffer
-    ByteBuffer bgr = image.slice();
+    TGAWriter writer = new TGAWriter();
+    writer.open(file, width, height, alpha);
+    ByteBuffer bgr = writer.getImageData();
 
     GL gl = GLU.getCurrentGL();
 
@@ -131,6 +110,8 @@ public class Screenshot {
     PixelStorageModes psm = new PixelStorageModes();
     psm.save(gl);
 
+    int readbackType = (alpha ? GL.GL_ABGR_EXT : GL.GL_BGR);
+
     // read the BGR values into the image buffer
     gl.glReadPixels(0, 0, width, height, readbackType,
                     GL.GL_UNSIGNED_BYTE, bgr);
@@ -138,8 +119,8 @@ public class Screenshot {
     // Restore pixel storage modes
     psm.restore(gl);
 
-    // close the file channel
-    ch.close();
+    // close the file
+    writer.close();
   }
 
   /**
diff --git a/src/classes/com/sun/opengl/util/TGAWriter.java b/src/classes/com/sun/opengl/util/TGAWriter.java
new file mode 100755
index 000000000..aafc7b47e
--- /dev/null
+++ b/src/classes/com/sun/opengl/util/TGAWriter.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2005 Sun Microsystems, Inc. All Rights Reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * - Redistribution of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ * - Redistribution in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * 
+ * Neither the name of Sun Microsystems, Inc. or the names of
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * 
+ * This software is provided "AS IS," without a warranty of any kind. ALL
+ * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
+ * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
+ * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
+ * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
+ * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
+ * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
+ * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
+ * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
+ * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
+ * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+ * 
+ * You acknowledge that this software is not designed or intended for use
+ * in the design, construction, operation or maintenance of any nuclear
+ * facility.
+ */
+
+package com.sun.opengl.util;
+
+import java.io.*;
+import java.nio.*;
+import java.nio.channels.*;
+
+/**
+ * Utility class which helps take fast screenshots of OpenGL rendering
+ * results into Targa-format files. Used by the {@link
+ * com.sun.opengl.util.Screenshot Screenshot} class; can also be used
+ * in conjunction with the {@link com.sun.opengl.util.TileRenderer
+ * TileRenderer} class. <P>
+ */
+
+public class TGAWriter {
+  private static final int TARGA_HEADER_SIZE = 18;
+
+  private FileChannel ch;
+  private ByteBuffer buf;
+
+  /** Constructor for the TGAWriter. */
+  public TGAWriter() {
+  }
+
+  /**
+   * Opens the specified Targa file for writing, overwriting any
+   * existing file, and sets up the header of the file expecting the
+   * data to be filled in before closing it.
+   *
+   * @param file the file to write containing the screenshot
+   * @param width the width of the current drawable
+   * @param height the height of the current drawable
+   * @param alpha whether the alpha channel should be saved. If true,
+   *   requires GL_EXT_abgr extension to be present.
+   *
+   * @throws IOException if an I/O error occurred while writing the
+   *   file
+   */
+  public void open(File file,
+                   int width,
+                   int height,
+                   boolean alpha) throws IOException {
+    RandomAccessFile out = new RandomAccessFile(file, "rw");
+    ch = out.getChannel();
+    int pixelSize = (alpha ? 32 : 24);
+    int numChannels = (alpha ? 4 : 3);
+
+    int fileLength = TARGA_HEADER_SIZE + width * height * numChannels;
+    out.setLength(fileLength);
+    MappedByteBuffer image = ch.map(FileChannel.MapMode.READ_WRITE, 0, fileLength);
+
+    // write the TARGA header
+    image.put(0, (byte) 0).put(1, (byte) 0);
+    image.put(2, (byte) 2); // uncompressed type
+    image.put(12, (byte) (width & 0xFF)); // width
+    image.put(13, (byte) (width >> 8)); // width
+    image.put(14, (byte) (height & 0xFF)); // height
+    image.put(15, (byte) (height >> 8)); // height
+    image.put(16, (byte) pixelSize); // pixel size
+             
+    // go to image data position
+    image.position(TARGA_HEADER_SIZE);
+    // jogl needs a sliced buffer
+    buf = image.slice();
+  }
+
+  /**
+   * Returns the ByteBuffer corresponding to the data for the image.
+   * This must be filled in with data in either BGR or BGRA format
+   * depending on whether an alpha channel was specified during
+   * open().
+   */
+  public ByteBuffer getImageData() {
+    return buf;
+  }
+
+  public void close() throws IOException {
+    // close the file channel
+    ch.close();
+    buf = null;
+  }
+}